Proto-Slavic *pъtakъ

→ Czech pták (inherited)

→ Kashubian ptôch (inherited)

→ Lower Sorbian ptašk (derived)

→ Upper Sorbian ptak (inherited)

→ Lithuanian paukštis (cognate)

→ Polish ptak (inherited)

→ Polish ptok (inherited)

→ Russian птах (inherited)

→ Russian птаха (inherited)

→ Rusyn птах (inherited)

→ Slovak vták (inherited)

→ Silesian ptŏk (inherited)

→ Ukrainian птах (inherited)

→ Old Czech pták (inherited)